OOP 1 Challenges

final_grade.rb

class FinalGrade
  attr_reader :student, :avg
  def initialize(argument)
    @avg = argument[:avg]
    @student = argument[:student]
  end

  def letter_grade
    return "A" if @avg >= 90
    return "B" if @avg >= 80 && @avg < 90
    return "C" if @avg >= 70 && @avg < 80
    return "D" if @avg >= 60 && @avg < 70
    return "F" if @avg < 60
  end
end

grade_output.csv

grade_reader.rb

require "csv"

class GradeReader
  attr_reader :students

  def initialize(file)
    @file = file
    @students = []
  end

  def parse_file
    CSV.foreach(@file, headers: true) do |row|
      @students << row.to_hash
    end
  end

  def individual_student
    student_info = []
    @students.each do |student|
      grades = student.values
      name = grades.shift
      student_info << each_student(name, grades)
    end
    student_info
  end

  def each_student(name, grades)
    student_grades = { student: name, grades: grades }
    Student.new(student_grades)
  end
end

grade_summary.rb

class GradeSummary
  def initialize(students)
    @all_students = students
    @students_avg = 0
  end

  def student_final_grade
    @all_students.each do |student|
      student.calc_final_grade
      student.grade_output
    end
    class_avg
  end

  def class_avg
    @all_students.each do |student|
      @students_avg += student.calc_avg
    end
    puts "\nThe class average: #{@students_avg /= @all_students.count}"
  end

  def class_min
    min_grade = []
    @all_students.each do |student|
      grades = student.grades.map do |grade|
        grade.to_i
      end
        min_grade << grades.min
    end
    puts "The class min: #{min_grade.min}"
    min_grade.min
  end

  def class_max
    max_grade = []
      @all_students.each do |student|
        grades = student.grades.map do |grade|
          grade.to_i
        end
        max_grade << grades.max
      end
    puts "The class max: #{max_grade.max}"
  end

  def class_standard_deviation
    difference = []
    square_sum = 0
    @all_students.each do |avg|
      difference << (avg.calc_avg - @students_avg)
    end
    difference.each do |dif|
      square_sum += (dif**2)
    end
    data_values = @all_students.count
    puts "The class standard deviation:
    #{ Math.sqrt((square_sum / data_values))}"
  end
end

run_program.rb

require_relative "grade_reader"
require_relative "final_grade"
require_relative "grade_summary"
require_relative "student"

puts "What class would you like to load?"
file = gets.chomp
if File.exists?(file)
  grade_reader = GradeReader.new(file)
  grade_reader.parse_file
  individual_student_info = grade_reader.individual_student

  all_grade = GradeSummary.new(individual_student_info)
  all_grade.student_final_grade
  all_grade.class_min
  all_grade.class_max
  all_grade.class_standard_deviation
else
  puts "File #{file} does not exist."
end

student.rb

class Student
  attr_reader :student, :grades, :final_grade
  def initialize(arguments)
    @student = arguments[:student]
    @grades = arguments[:grades]
    student_info = { avg: calc_avg, student: @student }
    @final_grade = FinalGrade.new(student_info)
  end

  def calc_avg
    grades = @grades.map do |grade|
      grade.to_i
    end
    avg = (grades.inject(:+) / grades.count)
    return avg
  end

  def calc_final_grade
    puts "#{@student} average grade was #{calc_avg}."
    puts "Final grade: #{@final_grade.letter_grade}"
  end

  def grade_output
    CSV.open("grade_output.csv", "a+") do |csv|
      csv << ["#{@final_grade.student.split.reverse.join(" ")}","#{@final_grade.avg.to_f}","#{@final_grade.letter_grade}"]
    end
  end
end

student_grades.csv